If you want to see a flicker, look on the ground and look soon. Flickers are moving south.

The flicker is a species of woodpecker, but no matter. In migration, flickers are ground-loving birds. That's where the ants and the grubs are, and flickers love ants and grubs. They are woodpeckers, after all, but they choose to hunt differently than their kin.

Like other woodpeckers, though, flickers are cavity nesters. This means that at other times of the year, flickers will appear in wooded areas, including farm shelterbelts.

In spring and fall, however, they prefer what used to be called "the greensward," and properly still should be. A sward is an open area, and greensward could apply to a forest clearing, a lawn, a park or a pasture. Flickers show up in all of these situations.

Flickers are abundant in migration, and they nest regularly in our area. Nevertheless, they seem to be relatively unknown. Over the years that I've written this column, only one other species has prompted more calls, and that is a well-known one: the bald eagle. People who call about bald eagles are sure of what they've seen and excited to have seen it. People who see flickers are usually uncertain about what they've seen. They're looking for help identifying the bird.

The flicker has three field marks that help clinch identification, and it shares each of these with other woodpeckers. As with other woodpeckers, the tail is stiff and the bill is heavy, the better for hammering holes in trees or, in the flicker's case, digging in the ground. The overall pattern of the flicker's plumage resembles other woodpeckers, as well. It is mottled and there's a conspicuous white patch on the rump. This is best seen when the bird is flying away. Finally, the flicker has a red patch behind the beak, the so-called "malar patch." The bird guides often call this a moustache, though of course a moustache properly so called is a patch below the nose, which in humans is the visual equivalent — though not the anatomical one — of a bird's beak.

The trouble with flickers is that they are of a brownish cast rather than black and white, like most woodpeckers. There's also their behavior, of course, which is unconventional for woodpeckers.

Three subspecies

Further trouble arises because there are three flicker subspecies. One of these, the gilded flicker, need not trouble us. It occurs in the desert Southwest. The other subspecies both occur on the Great Plains. The common species in the Red River Valley is the yellow-shafted flicker. Farther west, the red-shafted flicker is more common. The flickers I saw growing up in Mountrail County had red shafts; the ones I see in Grand Forks County are yellow-shafted. In this context, the word "shaft" refers to the feathers on the underside of the wing. These show only in flight, but they are quite obvious on retreating birds.

Together, these subspecies share a common name, northern flicker, even though the species occurs throughout North America, except in the Arctic and Mexican interior.

In our area, most flickers are migrants, though some occasionally spend the winter. Exactly why most go south and some few stay farther north is not entirely clear. It may have to do with individual hardiness. Or it may have to do with the harshness of successive winters. For me, a flicker in winter is always a surprise, though I recognize that it also is always a possibility.